1. Field of the Invention
The present invention relates to a fuel supply device that feeds an internal combustion engine with a fuel, and more particularly to a fuel supply device for an internal combustion engine that is equipped with a fuel conversion device.
2. Description of Related Art
In the related art, there has been proposed an internal combustion engine in which an in-tank fuel (such as cyclohexane or the like, that is a before-convention fuel led into a fuel tank from the outside) is reformed into hydrogen and a high-octane fuel (e.g. having a benzene nucleus) by a dehydrogen-reforming reaction. Such hydrogen and high-octane fuel are fed to the engine to combust in the engine, such that a low load fuel consumption performance in a lean-burn operation using the hydrogen is improved, and a high load output performance in a high compression ratio with the high octane fuel is also improved.
In a fuel supply device to which the above-mentioned fuel reforming system is applied, when the original fuel (viz., in-tank fuel) before being reformed is composed of only naphthenic hydrocarbons such as cyclohexane or the like, all of the original fuel can be reformed into a reformed fuel and fed to the engine. However, when the original fuel is a fuel (for example, gasoline) that is available on the market, it is impossible to reform all of the fuel components, and thus, it is necessary to also feed the engine with the original fuel for combustion in the engine. For this reason, the fuel supply device to which the above-mentioned fuel reforming system is applied is effective in case of using a fuel (such as gasoline or the like) that has a relatively low boiling point as the original fuel. However, in case of using a fuel (for example, light oil or the like) that has a relatively high boiling point as the original fuel, undesired fuel flow on the walls of intake ports and combustion chambers tends to occur which causes the problem of increased unburnt HC (Hydrocarbons) and PM (Particle Materials).